Power over Ethernet

Power over Ethernet (PoE) has been introduced for many years, but the latest standard IEEE 802.3bt improves the maximum power that can be transmitted through twisted pair Ethernet cables. The new standard was approved and introduced in 2018, prompting the development of many new PoE applications. Now, power supply equipment (PSE) can provide up to 100W of power, supporting 8 different power levels; Power consuming devices (PDs) will be able to use up to 71W of power, suitable for Ethernet cables up to 100m in length. In addition, the adoption of the new PoE standard mainly depends on the ability to improve the power density on the power supply equipment (PSE) side while maintaining the same overall size.

Electrical Equipment - Design a Reliable and Energy Efficient DC-DC Power Supply for PoE PD

Infineon provides a variety of reliable and efficient high-voltage and low-voltage MOSFETs, as well as various DC-DC converter solutions, such as power management ICs (PMICs) or switch regulators, as well as OptiMOS ™ Low voltage MOSFET, CoolMOS ™ High voltage MOSFETs and CoolSET for AC-DC auxiliary power supply ™ Auxiliary converter system.

Power supply equipment - can be powered through twisted pair Ethernet cables

Thanks to technical progress and the newly launched IEEE 802.3bt standard, the power of power over Ethernet has been improved, up to 100W. This development trend has brought challenges to the design of the main power supply suitable for PoE power supply equipment (PSE). Whether upgrading existing Ethernet designs to integrate PoE devices or adding a few PoE ports that comply with the IEEE 802.3bt standard, it will significantly increase the power requirements of the overall power budget. Based on the overall power budget and power topology, we divide the power supply equipment into two power levels.

Power supply equipment with power lower than 250W

The main power supply adopts a flyback topology design with source clamping. Due to the low available power, cost optimization solutions can be implemented for a few PoE ports that support the IEEE 802.3bt standard. Therefore, multiple new requirements have been put forward for PoE power supply equipment: · As the required power for each newly added port can reach up to 100W, the output power is correspondingly increased, resulting in an increase in PoE power distribution · The improvement in efficiency and power requirements leads to the replacement of active clamp flyback (ACF) by resonant LLC SMPS topology structure · The output power is increased, and it is necessary to increase the power density to maintain the current appearance specifications · High efficiency, Suitable for various load conditions of the main power supply. In addition, many PoE power supply equipment (PSE) controllers require external power MOSFETs to safely control port power. Low RDS (on) and wide secure workspace (SOA) ensure system efficiency while providing security margin to protect the system from faults.

Power supply equipment with power higher than 250W

Infineon provides a variety of semiconductor products suitable for advanced power supply equipment (PSE) power design, and is also the only manufacturer that can provide complete and suitable semiconductor product solutions for power supply equipment (PSE): from high-voltage CoolMOS ™ MOSFET and Low Voltage OptiMOS ™ MOSFET to SiC and XMC series microcontrollers and CoolSET ™ Auxiliary converter system. Selectable CoolGaN ™ The technology meets the increasing power requirements of rack mounted systems.